1. Field of the Invention
The invention pertains to a device for Vee-grafting, especially for hard-and-stone-fruit trees, with an angled knife for cutting a groove in the stock arranged to move in an outer part, formed as a guide space by means of a toggle lever, which is inclined in relation to the axis of the stock.
A prior art device for cutting a notch is described in DE-B-157 072. An angled knife is manually moved with a lever in a frame inclined against the stock such that a notch is cut with an increasing depth. With that device, however, a diametrically opposed wedge on the shaft of the scion cannot be made. As a consequence, such grafting must be made manually, whereby the forming of a notch in the stock and in the diametrically opposed wedge on the end of the scion generally takes a lot of time. In addition, the section planes become easily contaminated, presenting a risk for the grafting operation. It is further disadvantageous that the device cannot be disposed on stocks with arbitrary diameters if the length relative to the depth of the notch in the wooden part should be the same.
It is therefore the object of the invention to provide a grafting device with which the above-mentioned drawbacks can be avoided.
2. Summary of the Invention
According to the invention, this object is attained in that there is an inner part moveable inside the outer part in the forward region or front end of which the knife is fitted. In the rear region there is an aperture for the scion where the outer part has an aperture in its forward region for the stock and in this rear region it has an aperture which can be positioned coincidentally with the aperture in the inner part and it also has an angled knife at the forward edge.
With such a device the above-mentioned object can be attained in an advantageous manner. The process includes the following steps: moving the inner part to its starting position along a direction B to the right-hand side, and moving the inner part consecutively to the left-hand side within the outer part. During that movement in the direction A, the knife disposed at the forward end of the inner part is guided through the aperture in the forward region of the outer part in an inclination angle Alpha against the stock, which projects through this aperture, wherein the aperture and its length and depth is formed by the intersection of the stock with the outer part.
In that way the notch is formed in the stock in a length and depth given by the special construction of the outer part.
In the same or in a second operation, in which the inner part is moved back to its starting position, the scion is led approximately in a counter angle Alpha' to the angle Alpha through the rear apertures of the inner and outer part at the same time and in the same position. During a following movement of the inner part, in direction A, to left-hand side the shaft of the scion is pushed against the knife disposed at the forward edge of the rear aperture in the outer part cutting the wedge on the shaft. The knife of the outer part has the same shape as the knife of the inner part. Therefore, the notch in the stock and the wedge on the shaft of the scion have the same geometry also and can be combined in a close fit.
As these working procedures can be made very shortly one after the other and without a possible contamination of the intersection planes, the success of the grafting cannot be affected by drying out or by insufficient cleanliness during the process.
According to a further advantageous embodiment of the invention, the parts moveable within each other and the knives disposed on them are V-shaped, whereas the knife for cutting the notch in the stock has a smaller aperture angle, preferably about 3 degrees, than the knife for cutting the wedge on the scion shaft so that it can be fitted into the notch by force fit. Preferably the V-edges of the knives are rounded.
When using scions with shaft diameters of 7 to 10 mm it is advantageous if the rear aperture of the inner part has a length of about 4 or 5 cm in the line of the cutting edge. Then the wedge of the scion is approximately of the same length and the depth of the wedge or the notch, respectively, is in that case about 5 to 8 mm.
If the respective barks of the stock and the scion are of a very different thickness, the depth and the length of the notch in the stock should be greater than the wedge of the scion so that, in spite of the thick bark, the cutting depth in the wood of the stock and the wedge are the same. This can be attained by adjustable edges of the outer part. They can be rotated in an upward direction or moved in a forward direction. Because of a greater aperture, the notch has a longer and deeper intersection depth than the wedge on the scion shaft.
It is also very advantageous to form the rear aperture in the inner part as the intersection of a cylinder inclined to the cutting edge. A scion fitting in this aperture can be easily held in a given angle position during cutting of the wedge. Especially for scion shafts not fitting exactly into the aperture of the inner part, it is advantageous that an abutment is situated at the forward end of the aperture against which the scion shaft is pressed by the toggle lever during the cutting of the wedge and thus held in the desired way. For holding the scion while cutting an additional locking lever disposed on the toggle lever, proves to be advantageous. In the starting position, this locking lever first presses the scion shaft against the abutment without moving it lengthwise and then, after locking it, moves it together with the inner part in forward direction.
In a further embodiment the forward and backward regions of the inner and outer parts are separated from each other and arranged parallel or one above the other and the inner parts are actuated either together or individually. In that way the device is shortened and especially the taking in and taking out of the scion is easier because of the better accessibility. The remaining wood parts can be pushed out easier after cutting.
A further advantageous possibility consists in moving in the inner part a locking part, which is moved backward against a stopper for releasing the scion shaft from the inner part and is moved against the shaft for locking and pressing it against the abutment and moving it together with the inner part forwardly for consecutive cutting.
Furthermore, it is advantageous that the shaft of the scion penetrating through the coinciding apertures in the inner and outer parts is ventured by a pushing tube which supports the translatory motion against the knife in the outer part.
Preferred embodiments are described in connection with the accompanying drawings. Modifications not specifically described, however, may be made without departing from the scope of the invention. Especially the general usefulness of the device should be noted, e.g. for vine cultures and for ornamental trees.